Ted: Hey, how was the big couples' night with Marshall and Lily?
Robin: Brutal.
Ted: Really? How?
Barney: It was like we were on a date with a sad, chubby girl our mom made us call.
Robin: And they were so nervous, that they weren't even making sense half of the time.
[flashback to Barney and Robin in Marshall and Lily's apartment:]
Lily: Hey. Come on in. Would you like a margarita?
Marshall: In Cabo, I saw Sammy Hagar eating a Belgian waffle!